1. Field of the Invention
This invention is directed to an apparatus and method for detecting pilot-induced oscillations (PIOs), and for controlling the pilot's input to the aircraft's flight control system to eliminate the PIO.
2. Description of the Related Art
Pilot-induced oscillations (PIOs) have long been recognized as a significant aircraft safety problem. A PIO results from undesirable interaction between a pilot and an aircraft, that drives the aircraft into control instability. PIOs have occurred in a large variety of civilian and military aircraft, and aviation history is replete with incidents in which the occurrence of a PIO resulted in aircraft damage or destruction, or pilot injury or death. For example, PIOs have been responsible for many aircraft accidents including crashes of the X-15, M2-F2 and the YF-22, and near-disasters involving the U.S. space shuttle, the Soviet Buran shuttle and the YF-16.
In an effort to prevent PIOs from ever arising, aircraft are stringently designed and tested under a variety of conditions. Nonetheless, even with such intensive design and test efforts, aircraft and/or pilot behavior can lead to PIOs and resulting disasters, as evidenced by the above-noted aircraft accidents. It would therefore be highly desirable to be able to stop PIOs at their onset before they become so serious as to result in an accident.